skim_expand

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries full burden. It only states it returns exact verbatim lines and that ranges work for skeleton lines. It does not disclose error behavior, prerequisites beyond a handle, or idempotency. Minimal behavioral context.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences: the first states the core purpose, the second adds details on input types. Every sentence is necessary, no fluff. Front-loaded with key information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool is simple (2 string parameters, no output schema). The description covers what the tool returns and acceptable inputs, but lacks details on handle validity, error handling, or ordering. It is adequate but not fully complete for an agent.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The description explains the 'anchors' parameter can be anchor ids or literal line ranges, adding meaning beyond the schema. However, the 'handle' parameter is not described (only implied from context), and schema coverage is 0%, so the description partially compensates.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool returns exact verbatim source lines for anchor ids from a skim_open result. It specifies the verb 'return' and resource 'source lines', and distinguishes from siblings by mentioning skim_open as the source.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies the tool should be used after skim_open by referencing 'from a skim_open result', and explains acceptable input types (anchor ids or line ranges). However, it does not explicitly state when not to use it or mention alternatives like skim_search.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.